Geobios

Published by Elsevier
Online ISSN: 0016-6995
Publications
Article
The camerate crinoids Hexacrinites hieroglyphicus (Goldfuss, 1839) and H. marginatus (Schultze, 1866) are valid species known from the Lower Givetian of the synclines of Gerolstein and Hillesheim, Eifel Hills (westernmost Germany). As shown by the refigured holotypes and new material, they are mostly separated by the expressed ornamentation of radials and basals. The radials of H. hieroglyphicus are characterized by prominent, variously formed bulges, stretching preferably in a radiate pattern across most of the plates. They do not reach the low plate boundaries. Vice versa, H. marginatus shows expressed depressions in the central part of the plates, but raised plate margins. The first known crowns of H. marginatus are described; one of them is proposed as neotype for the lost original.RésuméLes crinoïdes Camerata Hexacrinites hieroglyphicus (Goldfuss, 1839) et H. marginatus (Schultze, 1866) sont des espèces valides, connues dans le Givétien inférieur des synclinaux de Gerolstein et de Hillesheim dans l’Eifel (ouest de l’Allemagne). Comme le montrent les holotypes refigurés et le nouveau matériel, elles sont séparées essentiellement sur l’ornementation bien exprimée sur les plaques radiales et basales. Les radiales de H. hieroglyphicus sont caractérisées par des bourrelets proéminents, de forme variée, disposés suivant un motif radiaire et recouvrant la quasi-totalité des plaques. Ils n’atteignent pas les sutures inférieures des plaques. De son côté, H. marginatus montre des dépressions bien exprimées dans la partie centrale des plaques mais avec la marge des plaques relevées. Les premières couronnes de H. marginatus sont décrites ; l’une d’elle est proposée comme néotype en remplacement de l’original disparu.
 
Article
The Lower Devonian genus VlastaBarrande, 1881 (Vlastinae, Antipleuridae) represents the oldest known bivalve with a sinistrally twisted shell, that relates to a shallow endobyssate mode of life in unstable biodetrital sediment. Detailed study shows that the shells lacked the gapes described by Barrande in the last century. The subfamily Vlastinae, originally established for Lower Paleozoic Bivalvia having large shell gapes, cannot include the genera ShaninaReed, 1924 and ShaninopsisIsberg, 1934. Vlasta occurs in Bohemia, Morocco and probably in Central Asia as a single, highly variable species, Vlasta bohemicaBarrande, 1881.RésuméLe bivalve VlastaBarrande, 1881 (Vlastinae, Antipleuridae) du Dévonien inférieur est la plus ancienneforme connue avec une coquille senestre, liée à un mode de vie dans le sédiment biodétritique instable d'une mer peu profonde. L'étude détaillée révèle que les coquilles n'avaient pas les bâillements décrits par Barrande au siècle dernier. La sous-famille Vlastinae, originellement établie pour les bivalves du Paléozoique inférieur avec de larges baîllements de la coquille, ne comprend pas les genres ShaninaReed, 1924 et ShaninopsisIsberg, 1934. Vlasta est représenté en Bohême, au Maroc et probablement en Asie centrale par une seule espèce à grande variabilité, Vlasta bohemicaBarrande, 1881.
 
Article
Lower Bajocian (Propinquans and Humphriesianum zones) reef-building corals of France are rather poorlydiversified: 16 to 19 genera (including morphogenera) and 17 to 26 species. The new genus Atelophyllia is created and the poorly known genus Ebrayia is revised. Synonymies of species are well understood, owing to a statistical analysis of populations sampled in the field (1410 samples, 900 thin sections). The taxonomic list and statistics offer the first paleoecological tool to study the trends of diversity. Because this diversity increases southwards (South Jura, Mâconnais), it suggests that a climatic control underlies the diversity gradient. Functional morphologic analysis of the various taxa offers a second method to evaluate ancient light intensities and sedimentation rates. For instance, a comparison with Montastrea, a recent zooxanthellate coral, shows that the variations of the colonial shape of Isastrea are light-dependant. An interpretation of Bajocian bioherms as lithoherms built by nonzooxanthellate corals must be rejected. The average annual growth rates of Bajocian corals are very low. The new findings suggest evolutionary and climatic explanations.
 
Article
New material from the Lower Paleocene of the Oulad Abdoun Basin, Morocco, including postcranial material permits a new description of Argochampsa krebsi. The odontoid process of the axis bears a strong lateral apophysis, continuous on the anterolateral margin of the centrum. This process has never been observed such developed in other crocodylians. The single preserved posterior cervical vertebra exhibits a particularly short neural spine, much shorter than that is observed in Alligator mississippiensis, Crocodylus porosus, and Gavialis gangeticus. A phylogenetic analysis, including new coding of A. krebsi, provide a result that is globally congruent with previous works, but differs significantly in the relationships of the gavialoids. A. krebsi is more closely related to G. gangeticus than is Eogavialis africanum. The South American Ikanogavialis gameroi and Gryposuchus colombianus form a polytomy, and are more closely related to G. gangeticus than is Piscogavialis jugaliperforatus, a gavialoid from Peru. The South American gavialoids may thus not be monophyletic. This result may indicate, contrary to previous result, a more complex paleobiogeographic history. Thus, a multiple invasion of South America by gavialoids from Africa is equally parsimonious with a single invasion, and an invasion from South American to Asia is equally parsimonious with an invasion from Africa.
 
Article
Statistical analysis of ostracode population from sixty-eigth recent samples in the Huelva littoral (SW Spain) delimited six groups, according to number of individuals (total and live), adult/instar ratio and energy. Results were applied to twenty-nine Pliocene samples, with revision of some conclusions derived from the study of another fossil groups.
 
Article
The site of Ahl al Oughlam has yielded the first important carnivore fauna of North Africa, and one of the richest of Africa. It includes 23 taxa, 13 of which are new, belonging to most of the carnivore families, mainly the Felidae (6 species), Hyaenidae and Mustelidae (4 species each). Several genera were not previously known from North Africa, like Pliocrocuta, Chasmaporthetes, Nyctereutes, Prepoecilogale, while the walrus (Alachtherium) is mentioned for the first time in Africa. Many other genera were unknown in the area earlier than the Middle or late Pleistocene: Herpestes, Viverra, Genetta, Acinonyx, Ursus, Poecilictis, Mellivora, Lutra. The carnivore fauna of Ahl al Oughlam, quite diverse ecologically, is at least as distinct from those of Eurasia as from those of Eastern and Southern Africa; the many similarities with both, however, allow to confirm the age previously proposed for the locality, ca. 2.5 m.y.
 
Article
The oldest mammals of the Betic Cordillera are reported from the Marine-Lagoonal Formation of the internalPrebetic. Only four species were found: Blainvillimys cf. langei, Eucricetodon sp., ex group atavus, Eomys sp., and Gliravus sp. The fauna is dated as Early Oligocene. This age is in contradiction with the previously assumed Chattian age of the base of the Formation, based on benthonic foraminifera found in other localities.RésuméLes plus anciens mammifères des Cordillères Bétiques sont décrits de la Formation Marine-Lagunaire du PrébétiqueInterne. La faune ne comprend que quatre espèces: Blainvillimys cf. langei, Eucricetodon sp., ex group atavus, Eomys sp., et Gliravus sp. La faune est datée comme Oligocène Ancien. Cette datation est en contradiction avec l'âge Chattien supposé jusqu'à maintenant pour la partie basale de la Formation, à base de foraminifères benthoniques.
 
Article
The paleozoic marine algae of Central Asia were recently investigated and attributed to warm-water and Tethyan microflora. If the majority of the taxa (114 out of 117) were already described from other basins, a few elements merit attention. Two chlorophyte species are new (Atractyliopsis nuratauensis nov. sp., Amarellina moscoviensis nov. sp.) and a new Hoeegonites sp. is left in open nomenclature. The flora also contains representatives of the puzzling Moniliporelleae, a rhodophyte family only reported from Kazakhstan with the genus Furcatoporella. An unusual in situ cluster of calcispheres is also illustrated.RésuméLa microflore d'algues marines calcaires du paléozoïque de l'Ouzbékistan a été illustrée pour la première fois et attribuée à des flores d'eaux chaudes ou téthysiennes (117 taxa sont reconnus). Si la grande majorité des espèces a été décrite dans d'autres bassins, certains éléments sont taxonomiquement intéressants. Deux espèces de Chlorophytes sont nouvelles (Atractyliopsis nuratauensis nov. sp. et Amarellina moscoviensis nov. sp.) ainsi qu'un représentant d'Hoeegonites sp. La flore comporte un représentant de l'énigmatique famille des Moniliporelleae (Rhodophyte, Furcatoporella). Enfin, une grappe in situ de Calcisphères est illustrée.
 
Article
Unusual “coralligenous” build-ups were found at the infra–circalittoral boundary from SE Sicily. They are columnar, rising up perpendicularly from the bottom, and consist of an inter-growth of encrusting algae and invertebrates. A selected build-up and its longitudinal section, together with some thin sections of selected parts, were studied to detail the growth structures, composition and fabric of the trapped sediments. The coralline algae show a succession of “concentric”, “fruticulose” and “foliaceous” structures. The framework delineates cavities bounded by algal thalli, sometimes filled by sediments. The organisms constituting the framework were grouped into functional guilds (Fagerström, 1991): “primary frame builders” (mainly coralline algae); “secondary frame builders” (vermetids, serpulids and some bryozoans); “bafflers” (erect, flexible bryozoans, some sponges and soft algae); “binders” (encrusting bryozoans, some crustose coralline algae and serpulids); “destroyers” (a few endolithic algae, rare sponges and bivalves); “dwellers” (brachiopods, foraminifers, bivalves, small bryozoans and some motile organisms). The distribution pattern of taphonomic features (composition, grain size and distribution of sediments filling cavities; presence of cement and its location; mineralogical composition and crystal size), together with interactions between growth structures and functional guilds, allowed one to distinguish three taphofacies, each recording different environmental conditions. They have been tentatively related with cyclic sequences testifying to local hydrodynamic regimes, with subsequent slighter and stronger intensity phases, during the last 2200 years.
 
Article
Fossil mammals remains from a newly discovered Miocene locality in the northern Sahara are described. Thislocality is situated to the North of Tademaït and is the most southerly located site of Miocene age in North Africa. The fauna includes a new Amphicyonine carnivore (Miacyon dojambir nov. gen. nov. sp.), two perissodactyls (Hipparion primigenium von Meyer, 1827 and Aceratherium sp.), an artiodactyl Palaeotraginae (Palaeotragus cf. germainiArambourg, 1959), and a proboscidea (Proboscidea indet.). The most abundant remains can be attributed to the two perissodactyls, while the other taxa are each represented by only single specimens. The presence of a primitive hipparionian-type Hipparion, the fact that Aceratherium is of small size, and the occurrence of an amphicyonine are the main arguments used in attributing the age of this locality to the Vallesian.
 
Article
En este trabajo se describe un nuevo basicráneo de titanosaurio (MML-194), en perfecto estado de preservación, proveniente del Cretácico Superior (Campaniano medio - Maastrichtiano inferior) de Río Negro, Argentina. Dentro de Titanosauria, el ejemplar recuerda a Bonatitan reigi más que a cualquier otro miembro del clado, en la presencia de una protuberancia supraoccipital recorrida por un surco medial (también presente en Saltasaurus y Rapetosaurus), las toberas basales prominentes, el foramen de salida para el nervio VII sobre la cresta proótica, el cóndilo occipital y el foramen magnum aproximadamente del mismo ancho. El material permite ver ciertas estructuras internas que no son apreciables en otros ejemplares de Titanosauria, como la cavidad pituitaria, la dorsum sellae, y los forámenes para la entrada de las carótidas internas. El material estudiado y Bonatitan fueron exhumados de un mismo nivel estratigráfico, la Formación Allen, de la cual también han sido colectados huevos fósiles asignables a saurópodos (megaloolitos), por lo que no es improbable que alguno de estos dos taxones haya sido el responsable de su puesta.
 
Article
This is the first description of Pliensbachian (Carixian and mainly Domerian) ammonite faunas from southern Turkey (Lycian Allochton, western Taurus). These faunas are from the Kısılka-Çorak unit (Kızılca locality, Tavas area) and from the Gümüslü unit (Ayıburnu Tepe and Kuru Dag localities). They consist of 32 species characterising seven biostratigraphic levels. Two new Carixian species are described: Lytoceras kisilcus nov. sp. and Fuciniceras lycius nov. sp. These Lycian faunas chiefly include Juraphyllitidae, Lytoceratoidea, Dactylioceratidae and Hildoceratidae. Conversely, Phylloceratidae are rather scarce. The faunas form a homogeneous assemblage of Mediterranean taxa clearly indicative of a South Tethyan paleobiogeographic affinity. The palaeobiogeographical analysis suggests for the Lycian Pliensbachian deposits a single area of sedimentation protected from oceanic influences by neritic barriers, possibly a basin between the Menderes and the Bey Dagları neritic platforms.
 
Article
A diverse avifauna is described from the lowermost Oligocene (MP 21) of the locality Boutersem near Bruxelles, Belgium. Remains of at least 13 avian taxa were distinguished and many are represented by more than one skeletal element. Coracoids of two anseriform taxa were identified, one of these is tentatively assigned to Paracygnopterus HARRISON and WALKER, 1979, the other is tentatively referred to Romainvillia LEBEDINSKY, 1927. Other anseriform bones are described but could not be assigned to one of the coracoids. The specimen referred to Paracygnopterus is the earliest certain record of the Anatidae and confirms the presence of this family in the lowermost Oligocene of Western Europe. Charadriiform birds are represented by at least four different species. Two of these are assigned to the new genus Boutersemia (Boutersemia belgica nov. gen. nov. sp., Boutersemia parvula nov. gen. nov. sp.). The genus Boutersemia is characterized by a large foramen vasculare distale on the tarsometatarsus and is tentatively assigned to the Glareolidae. Three species of rails (Gruiformes, Rallidae) were identified, two of which are classified in the new genus Belgirallus (Belgirallus oligocaenus nov. gen. nov. sp., Belgirallus minutus nov. gen. nov. sp.). The species of the genus Belgirallus are among the earliest substantial record of fossil Rallidae, and Belgirallus minutus is the smallest early Tertiary rail known so far. A fragmentary distal end of a tarsometatarsus has been assigned to the Pici and represents the earliest fossil record of this taxon. A distal end of an upper beak resembles that of recent Scolopacidae and Rostratulidae (Charadriiformes), but is much larger. Fragmentary tarsometatarsi of two large avian taxa probably belong to the Idiornithidae (Gruiformes) and Phoenicopteriformes.
 
Article
The discovery, in Antarctic rocks of the Middle Triassic, of leaves with Dicroidium anatomy attached to stems withundivided vascular cylinder and pycnoxylic wood of the widespread Dadoxylon type, calls into question the long-accepted reconstruction of Dicroidium fronds attached to Rhexoxylon stems. Although Dicroidium leaves are common throughout Gondwana, Rhexoxylon is known only from Western Gondwana (Argentina, Brazil and South Africa). The anatomy of the Antarctic axes, including the presence of numerous buds, suggests a plant with more complex architecture than that proposed in the reconstruction of Dicroidium in Western Gondwana. Two hypotheses for the belated discovery of this additional “Dicroidium plant” are proposed.RésuméLa découverte dans un gisement du Trias moyen d'Antarctique de feuilles à anatomie de Dicroidium attachées à des 0309 tiges qui présentent un cylindre vasculaire non divisé et du bois pycnoxylique de type Dadoxylon remet en question l'hypothèse classique selon laquelle les frondes de Dicroidium étaient portées par des axes de Rhexoxylon. Alors que les feuilles de Dicroidium sont largement représentées dans l'ensemble du Gondwana, Rhexoxylon est restreint à la partie ouest du continent (Argentine, Brésil et Afrique du Sud). L'anatomie des axes d'Antarctique, qui présentent en particulier de nombreux bourgeons, suggère que l'architecture de ces plantes était plus complexe que celle proposée pour la reconstruction de Dicroidium basée sur les restes du Gondwana de l'Ouest. Deux hypothèses sont proposées pour interpréter la découverte récente de cette nouvelle plante à frondes de Dicroidium.
 
Article
Newly discovered fossil localities in coarse-grained deposits of the Pennsylvanian and Permian Antler overlap assemblage in the southern Shoshone Range, north-central Nevada have yielded a low-diversity assemblage consisting chiefly of a new species of chonetoidean brachiopod: Dyoros (Lissosia) nevadaensis nov. sp. The subgenus Dyoros (Lissosia), is known from Leonardian and lower Guadalupian strata in North America, mainly in Texas. The coarse-grained lithology of the host strata, their unconformable relation on deformed lower Paleozoic rocks, and the Leonardian and(or) lower Guadalupian age indicated by Dyoros (Lissosia) provide evidence that host strata are younger than strata of the Antler overlap assemblage in nearby areas of the southern Shoshone Range and suggest that an unconformity of local extent may be present within the overlap assemblage. The fossil age ranges and lithologic data suggest that the host strata may be correlative with the Guadalupian Edna Mountain Formation, an unconformity-bounded unit that forms the upper part of the Antler sequence in the Battle Mountain area to the north. This correlation suggests that the unconformity beneath these strata may have regional extent in north-central Nevada. The origin of the inferred regional unconformity is unknown and may have resulted from relative changes of sea level or regional extensional or contractional tectonism in the area of the former Antler highlands, which forms the substrate for the Antler overlap assemblage.
 
Article
An abundant fauna of Scleractinian corals has been studied from a Mid Miocene (Serravallian) newoutcrop in the North Aquitaine Basin (SW France). It consists of more than fifteen taxa, with a noticeable diversification in the genera Flabellum and Balanophyllia; 10 of these taxa are new in the Miocene of the Aquitaine Basin. This is probably the richest assemblage of the French Serravallian. The name Flabellum montanaroae nov. nom. is set. Biogeographically, the studied locality bears witness to Northern, Atlantic and Mediterranean influences. The ahermatypic content of the fauna agrees with the observed general trends to a gradual disappearance of reefal species and to a cooling in neritic waters during the Mid Miocene along the Northeastern Atlantic frontage. In terms of paleoecology, the corals-rich deposit contains an abundant malacofauna, which indicates an infralittoral, euhaline, and fairly calm environment, with a marly-sandy substrate; this biofacies looks like the muddy facies of the modern assemblage SFBC (“Sables Fins Bien Calibrés”).
 
Article
Subfossil bird bones collected at two sites on Madagascar include specimens of two species of Aquila eagles, agenus previously unknown on Madagascar. It is not possible to determine if these specimens represent extinct or extirpated species.RésuméL'étude d'ossements d'oiseaux sub-fossiles provenant de deux localités de Madagascar a permis de mettre enévidence la présence des restes de deux espèces d'aigle appartenant au genre Aquila, genre jusqu'alors inconnu de Madagascar. Il n'est pas possible de définir si ces espèces du genre Aquila représentent des espèces aujourd'hui éteintes ou constituent des espèces dont la distribution actuelle ne comprend plus Madagascar.
 
Article
This paper deals with the detailed taxonomic study of the first mammal remains from the Marinio Formation in the Divisadero Largo area, Mendoza, central west Argentina. This area was well-known by the fossils recovered from the Triassic levels and particularly by the faunal assemblage from the Cenozoic levels corresponding to the Divisadero Largo Formation. Until recently, no mammal remains had been accurately reported for the Marinio Formation, Miocene in age. The specimen consists in an almost complete upper jugal series (teeth found separated from the maxillary bone except the M3) of a small Mesotheriidae (Notoungulata), which was preliminary identified as Mesotheriinae indet. The main characteristic of these teeth is their small size, significatively lesser than that of the Miocene genera Eu ypotherium, Typotheriopsis and Pseudotypotherium, being closer to Alycrotypotherium from Bolivia and the Chilean species from the Chucal Formation. The direct comparison with these latter forms has allowed a more detailed Study and the recognition of the material here described as cf. Altiopotherium chucalensis, with all cautions inherent to the incompleteness of the material. (c) 2007 Elsevier Masson SAS. All rights reserved.
 
Article
The composition of Jurassic marine ostracod and foraminiferal assemblages from the Neuquen Basin is analysed. The absence of these microfossils from certain levels is attributed to a number of causes, such as inimical facies for their existence or for their preservation. Evidence is produced demonstrating that the absence of ostracods and the virtual absence of Foraminifera from such important Middle Jurassic sections as that at Chacay Melehue is due to their lower bathyal or abyssal palaeodepth. The relative success of filter and deposit feeders is shown to be probably related to palaeoxygen levels, with filter feeders being able to tolerate lower levels of oxygen concentration than their competitors. The palaeoecology of the various ostracod assemblages is compared and contrasted with that of their contemporary Foraminifera. While in the Liassic and the early Middle Jurassic there is a considerable general similarity between ostracod assemblages wordwide, throughout the remainder of the Jurassic there is evidence of the progressive isolation of southern South America, with consequent generic impoverishment and the absence or extreme rarity of many of the major families and genera of NW Europe. Conversely, there are no genera or supra-generic taxa endemic to Argentina.
 
Article
Six new species of deep-sea cytheracean Ostracoda are described from the southwestern Pacific and eastern IndianOceans. The new species are Abyssobythere inequivalva, Cytheropteron anisovalva, C. dorsocorrugatum, C. lumalatum, C. parapulcinella and C. lobatulum. These species possess a hollow expansion of the shell above the hinge, forming a linear keel in all except in the latter species which has a laterally drooping dorsal lobe. We observe in some species that there is internal communication between the dorsal keel space and the interior of the duplicature. This suggests that the space has a particular function; various possible advantages inherent in the possession of such structures, including controlled buoyancy, are discussed.RésuméSix nouvelles espèces d'ostracodes marins profonds de la famille Cytheracea sont décrits. Ils proviennent du Sud-OuestPacifique et de l'Océan Indien oriental. Ces nouvelles espèces sont: Abyssobythere inequivalva, Cytheropteron anisovalva, C. dorsocorrugatum, C. lumalatum, C. parapulcinella et C. lobatulum. Elles possèdent toutes un prolongement creux de la coquille au-dessus de la charnière, qui forme un aileron, sauf chez la dernière espèce ou l'exroissance prend la forme d'un lobe qui pend latéralement. Nous avons observé chez certaines espèces une communication entre l'intérieur de l'aileron et la zone marginale interne, suggérant une fonction particulière pour cette structure. Les différents avantages liés à la possession d'une telle excroissance, en particulier au niveau de la flottabilité, sont discutés.
 
Article
Detailed micropaleontological investigations carried out over several decades by one of us (M.-F. P.) mainly in central and western Pyrenees (Bigorre, Béarn, Pays Basque) resulted in a subdivision of the Pyrenean Carboniferous into twelve conodont zones. An attempt is made herewith to compare and correlate this zonation with several equivalent subdivisions established throughout the world (Cantabric Mountains, North Africa, British Isles, Belgium, Germany and Central Europe, Donetz Basin, South China, and the USA).
 
Article
A new species of corvid assigned to genus Pica is described from Pedrera de s'Ónix (Mallorca), a fossil site referred to the Plio-Pleistocene boundary. The combination of osteological features in the fossil species is not fully coincident with any Palearctic Corvidae; the major resemblance is with Pica pica and to a lesser extend with Garrulus glandarius. Automorphic characters are present in the humerus, femur and quadrate. The generic attribution is based on the latter bone. A reduction of the wing elements and a lengthening of the leg is present in the fossil species, probably achieved through insular evolution. Ratios estimating relative proportions of wing and leg skeleton prove reduction in flight capability compared to recent Corvidae, although the trend is not as extreme as in the insular Traversia lyalli (Acanthisittidae) or Emberiza alcoveri (Emberizidae), the only truly flightless passerines known so far.
 
Article
The discovery of continental interstratified fossiliferous layers within the lower Miocene marine deposits of Bas Languedoc and the rather unexpected occurrence of rodents within the marine deposits of the same period enables us to refine the mammalian biochronological scale, but above all enables us to establish correlations between the latter and the marine stratigraphic scale. Thus the standard mammalian level of Paulhiac is correlated to the «formation bioclastique de Carry-le-Rouet. As for the standard level of Laugnac it might correspond to the marine Burdigalian whereas it is traditionally allocated to the Aquitanian.The abundance of rodents has allowed to complete our knowledge of still imperfectly known faunas and to formulate new data concerning some evolutive lineages of Cricetid, Eomyid and Glirid rodents.
 
Article
When studying the biology and ecology of Juliidaeliving representatives (Gastropoda, Opisthobranchia, Sacoglossa) a close relationship can be observed between these animals and green Algae of the genus Caulerpa (Chlorophycea, Siphonophycidae). The animal feeds on the host plant by sucking the sap of the Alga, and moreover seems to use the ingested chloroplasts for a functional photosynthesis. Each species of Juliidae is found living on only one (or sometimes two) species of Caulerpa.The fossil Juliidae prove the existence of Caulerpagrowing at the same places, though these algae do not leave any direct remnant of their presence. Applying this to the Paris Basin Eocene, where the Juliidae are relatively abundant and varied, a quite accurate estimate is given for many characteristics of the paleo-environment, by analogy with the narrow and strict ecological needs of the living representatives (bathymetry, temperature and oxygenation of water, and presence of Caulerpa sea weeds).A review of the Paris Basin eocene species is given, including their stratigraphical distribution and drawings of the shells.
 
Article
The Ypresian locality of Burnham-on-Crouch(Essex) has yielded numerous Selachian species, some of which are new: Hexanchus agassizi sp. nov., Scyliorhinus burnhamensis sp. nov., S. casieri sp. nov., S. pattersoni sp. nov., S. woodwardi sp. nov., Pararhincodon ypresiensis sp. nov., Triakis wardi sp. nov., Mustelus whitei sp. nov. The Hexanchid teeth classicaly refered to Notidanus serratissimusAg. include in fact two separate species belonging to different genera: Notorhynchus serratissimus (Ag.) and Hexanchus agassizi sp. nov. Lamna affinis (Casier) is arranged in the genus Isurolamna nov. in consideration of his dental peculiarities. The genus Burnhamia nov. is created for Rhinoptera daviesiWoodward that can be regarded as a Mobulid. Oxyrhina sheppeyensisCasier must be classified in the genus Anomotodon. The genus Triakis, Mustelus, Anomotodon and Pararhincodon are pointed out for the first time in the Ypresian.
 
Article
A specimen of the fern fructification RadiithecaBrousmiche et al., up to now only known in the Pilsencoalfield (Czech Republic), has been discovered in the late Westphalian D strata of the Sarre Lorraine coalfield. Relationships between Radiitheca dobranyanaBrousmiche et al. and Pecopteris waltoniiCorsin are discussed both on paleobotanical and palynological basis. TEM study of the Microreticulatisporites(Knox) Potonie & Kremp macerated from the French and Czech specimens led to the characterization of the unique layer of the spore-wall that is the exospore, This investigation has shown: (1) that the ultrastructural features of the spores from both localities are perfectly similar, (2) the nature of the bodies occurring in each lumen that were called “pustules” in Brousmiche et al. (3) and that the lack of these ones is only due to preservation or maceration bias. A comparison of the exospore ultrastructure with that of main groups of living ferns suggests close affinities between the genus Radiitheca and the Gleicheniaceae.
 
Article
A new species of a coralline sponge, Cassianothalamiazardinii n. gen. n.sp., from the Lower Carian Cassian Beds (northern Italy) is described. The new species possesses a secondary thalamid basal skeleton with a spongocoel and the internal structure is constructed of horizontal elements (trabecula) and vesiculae. The microstructure of the basal skeleton is composed of an irregular high Mg-calcite. From the spicular skeleton aster-microscleres can be preserved. In rare cases, monaxonid megascleres can also be found. Therefore the new sponge is probably a representative of the demospongid order Hadromerida.RésuméUne nouvelle espèce d'éponge coralline, Cassianothalamia zardiini n.gen. n.sp., a été trouvée dans les couches du Carnien inférieur de Saint-Cassian. La nouvelle espèce possède un squelette basal thalamide secondaire muni d'une cavité pseudogastrique et sa structure interne est constituée d'éléments horizontaux (trabécules) et de vésicules. La microstructure de la partie basale du squelette est composée d'une calcite irrégulière à forte teneour en Mg. Les microsclères astéroïdes du squelette spiculaire peuvent avoir été conservés. On peut aussi trouver très rarement des mégasclères monaxonides. Par conséquent, cette nouvelle éponge est probablement un représentant de l'ordre Hadromerida des Démosponges.
 
Article
Late Paleocene to early Eocene associations of ostracodes from Caravaca (South of Spain) are, at leastpartially, constituted of new species of which Trachyleberidea marginata nov. sp. is at the same time abundant and characteristic. Cytherella sp. 1 aff. navetensis, Bairdia cf. cymbula, Krithe sp. 1, Oerthella ? sp. 1 aff. aculeata and T. marginata are present throughout the section. Possible modifications of the infralittoral to epibathyal environment (sources of nutriment) are only indicated by the reduced abondance of carapaces. The Paleocene and Eocene species are partially the same, and therefore the Paleocene/Eocene boundary is, for the infralittoral to epibathyal environment, less abrupt than in NW Europe.ResumenLas asociaciones de ostrácodos del Paleoceno superior y del Eoceno inferior de Caravaca (Sur deEspaña) están, al menos en parte, constituidas de especies nuevas, tal como Trachyleberidea marginata nov. sp. que es a la vez abundante y característica. Cytherella sp. 1 aff. navetensis, Bairdia cf. cymbula, Krithe sp. 1, Oertliella ? sp. 1 aff. aculeata y T. marginata estàn presentes a lo largo de todo el corte. Las posibles modificaciones del medio ambiente, infralitoral a epibatial, sólo son sugeridas por la disminución del número de caparazones. Las especies paleocenas y eocenas son parcialmente comunes, y por tanto el límite Paleoceno/Eoceno es, para los ostrácodos de medio infralitoral a epibatial, menos marcado que en el NW de Europa.
 
Article
Biochemical characters and properties of intraskeletal organic matrices are studied in skeleton piecesfrom several growth zones sampled in a 25 cm long living Porites core. In experimental conditions these organic matrices exhibit an inhibitory effect upon CaCO3 precipitation which increases all along the 15–20 upper cm of the care. Parallely relative amino acid compositions are more and more enriched in aspartic and glutamic acids from the surface to the base of the core, and molecular weights of glycoproteic compounds are comparable to those of the upper most living zone in all parts of the core except in the base. From the combination of experimental results it is conchided that the highest inhibiting efficiency of organic matrices is a consequence of the quantity, the composition (Asp concentration) of organic matrices, and the preservation of high molecular weight assemblages. Consequences for cementation processes in superficial zones of coral reefs are examined. It is most probable that the diagenetic suate of intraskeletal organic matrices influences the development of cements directly upon the surface of skeletal substrates, as well as the formation of diagenetic aragonite overlaying biogenic aragonite within skeletal structures. Conditions in reefal cryptic zones inhabitated by sponges are discussed as a comparison with photic zones where seleractinian corals are located.
 
Chitinozoans from the Aut~is-Mirim Fm, Amazonas Basin, and the Benjamin Constant Fm, Solim/3es Basin. (1 and 6 : Aut~s-Mirim Fm ; 2-5 and 7 : Benjamin Constant Fin). 1, ttmawteoabtttna nt&ertaa ? (BOUCHIg, 1965) (x 420). Well I-AM-I-AM, depth 2091 m. Petrobr~ls research center collections. CEN-PES no. G 16/98525. 2-3, Cono¢btttna dectpiens TAtJGOURDEAtJ & JE.KHOWSKY, 1960. 2, (x 260). Well 1-JD-1-AM, depth 2590 m. Petrobr~s research center collections. CENPES no G 2/11713. 3, (x 180). Well 1-JD-1-AM. depth 2555 m : Petrobr~s research center collections. CENPES no. G2/11703. 4.5, ConoaBltina Bavlt~ekt ? PARIS & MERGL, 1984. 4. (x 220)'. Well 1-JD-1-AM. depth 2581 m. Petrobr~ts research center collections. CENPES no. G 1/90815. 5, (x 640). Well 1-JD-1-AM, depth 2581 m. Petrobr',ts research 
Chitinozoans from the Benjamin Constant Fm, Solim/Ses Basin, and the Aut~is-Mirim Fm, Arazonas Basin. (1-4, 6-7 : Benjamin Constant Fin, 5 : Aut~is-Mirim Fm). 1,2, Conocbitina l~rmdgata ? (UMNOVA, 1969). 1, (x 260). Well 2-BT-1-AM, depth 1106 m. Petrobr~is research center collections. CENPES no. G 2/11712. 2, (x 280). Well 1-JD-1-AM, depth 2581 m. Petrobr~is research center collections. CENPES no. G 1/90807. 3-4, ¢onochitina sp. A. 3, (x 380). Well 1-JD-1-AM, depth 2590 m. Petrobr~fs research center collections. CENPES no, G 2/11706. 4. (x 400). Well 2-BT-1-AM, core 18 (1096 m). Petrobr~is research center collections. CENPES no G 1/90810. 5. Conacbittna sp. B. (x 560). Well 1-AM-l-AM, depth 2091 m. Petrobr~s research center collections. CENFES no G 16/98533.-6-7, Cyatbocbittna campanulaefarrats (EISENACK, 1931). 6. (x 325). Well 1-JD-1-AM, depth 2581 m. Petrobnfs research center Paleozoic slide collections. Slide no. 336. 7, (x 435). Well 1-JD-1-AM, depth 2581 m. Petrobr~s research center Paleozoic slide collections. Slide no 336. Cbittnozoaires de la Formation da Autd~.Mirim, Bassin de l'Amazone, et la Formation de Benjamin Constan~ Bassin de Solim~es. (1-4, 6-7 : Formation de Benjamin Constant ; 5 : Formation de Autdts-Mtrim). 
Chitinozoans from the Aut~is-Mirim Fm, Amazonas Basin, and the Benjamin Constant Fm, Solim6es Basin. (1, 3-7 : Aut~is-Mirim Fm ; 2 : Benjamin Constant Fm). I, BtsenacktBna sp. (x 540). Well 1-AM-I-AM, depth 2091 m. Petrobr~fs research center collections. CENPES no. G 16/98532. 2, Lagenoebtttna abel!gts PARIS, 1981. (x 540). Well 1-JD-1-AM, core 18 (1096 m). Petr6tr~is research center collections. CENPES no. G 1/90806. 3, ROabdocbtttna graatlts ? EISENACK, 1962. (x 160). Well 1-AM-I-AM, depth 2091 m. Petrobr~s research center collections. CENPES no. G 16/98524. 4, Lagenocbtttna tmusstca ESSENACK 1931 (X 400). Well 1-AM-I-AM, depth 2091 m. Petrobr',is research center collections. CENPES no. G 16/98534. 5, Tamwhtttna anttcosttenMs (ACHAB, 1977). (x 220). Well 1-AM-l-AM, depth 2091 m. Petrobr~s research center collections, CENPES no. G 16/98531.6,7, Tanmcbtttna byalophrys (EISENACK, 1959). 6. (x 630). Well 1-AM-l-AM, depth 2091 m. Petrobr~is research center collections. CENPES no. G 15/98520. 7. (x 140). Well 1-AM-l-AM, depth 209 m. Petrobr~is research center collections. CENPES no. G 16/98519. Chitinozoaires de la Formation do Autds.Mirim, Bassin de l'Amazono, at la Formation de Benjamin Constan~ 
Article
Marine sedimentary rocks of Ordovician and supposed Ordovician age have been investigated for chitinozoans in five Paleozoic basins of Brazil, viz. Solimoes, Amazonas, Parnaiba, Jatoba, and Parana basins. The lithology is predominantly sandstones with subordinate siltstones and shales. In the Solimoes Basin, the basal Paleozoic Benjamin Constant Formation yielded a characteristic north Gondwana assemblage of late Arenig to early Llanvirn age. Overlying beds are of Silurian age. Within or in connection to the Parnaiba and Parana basins continental sedimentation occurred in restricted basins with molasses and acid to intermediate igneous rocks of supposed Early - Middle Ordovician age. A more widespread transgression started probably in late Caradoc and gave rise to the first Paleozoic marine sedimentation of the Amazonas (Autas-Mirim Fm), Parnaiba (lpu Fm), possibly Jatoba (Tacaratu Fm), and Parana (Rio Ivai Fm) basins. A diagnostic Ashgill (Rawtheyan) chitinozoan assemblage is present in the upper part of the Autas-Mirim Fm. The Ordovician-Silurian boundary lies approximately at the boundary between the Autas-Mirim Fm and the overlying Nhamunda Fm. No contemporary chitinozoan faunas are known elsewhere in Brazil.
 
Article
Subfossil bones collected on Réunion Island by B. Kervazo in 1974 have provided further evidence of the past avifauna of the island. The remains of six extinct species have been excavated from a cave. A new genus and three new species are described. Two species previously recorded only from Mauritius and an incomplete bone of the extinct Réunion Ibis Borbonibis have also been discovered.RésuméDes ossements subfossiles recueillis par B. Kervazo à La Réunion, en 1974, apportent de nouveaux éléments concernant l'avifaune historique de l'île. Des fouilles effectuées dans une caverne ont permis de trouver les restes de six espèces éteintes, comportant un genre nouveau et trois espèces nouvelles. Deux espèces connues auparavant seulement à l'île Maurice et un fragment d'os correspondant à l'ibis éteint de La Réunion, Borbonibis, ont également été découverts.
 
Article
The history of the taxa of Mimosaceae fossil woods is signalized after the search of their species and their diagnosis. It allows to count them and to show the ways the palaeobotanists do it. Fifteen genera and sixty eight species are counted, three genera are eliminated, three species are denominated again.
 
Article
This paper deals with the chronostratigraphic position of the San Emiliano Formation (lower Upper Carboniferous of the Cantabrian Mountains, Spain), which contains marine as well as continental fossiliferous strata, and therefore provides the elements for a correlation between East and West-European chronostratigraphic schemes. These studies have been carried out in the type-section, near the village of San Emiliano, and in the Bernesga Valley, near Villamanin. Important for the determination of its stratigraphic position is the presence of continental nora, brachiopods, and fusulinid foraminifera, at various levels in the formation. Hence, data on nora and fauna with a bearing on the stratigraphic position of the formation are reviewed, with special attention to fusulinid foraminifera. Additional data on the fusulinid content in some localities in the type-area are also presented on the basis of a collection of thin sections described by Carballeira et al. (1985). The results of some earlier studies, from 1965 to 1988, on the identification and dating of fusulinids, are compiled and, whenever necessary, modified. Conclusions are drawn from the analysis of data on the age of the various subdivisions of the formation. The revised biostratigraphic information on the San Emiliano Formation allows to suggest correlations between the relevant parts of the chronostratigraphic classifications of West and East Europe. It seems that the Lower/Upper Bashkirian boundary and that between the Namurian and the Westphalian more or less coincide. The Bashkirian/Moscovian boundary probably corresponds to the interval between Upper Westphalian A and basal Westphalian B. This is a lower position than that admitted in the Donets Basin where it has generally been correlated with the Westphalian B/C boundary.
 
Article
The first Carboniferous conodonts studied from the Cares river section correspond to fifteen species and one subspecies from seven genera, some of them reported from the Picos de Europa Unit for the first time. The conodonts belong to several zones between the upper Tournaisian and the upper Serpukhovian-lower Bashkirian. Furthermore, the species Idiognathodus incurvus Dunn is reported for the first time in the Cantabrian Mountains and southern Europe, from upper Bashkirian or lower Moscovian beds.
 
Article
Lazarussuchus inexpectatus, nov. gen., nov. sp. from the Oligocene, is a new form of Choristodera which extends the longevity of this clade into the Middle Tertiary. It bears a remarkable assemblage of primitive characters. In this respect it is similar to the middle and late Jurassic form, Cteniogenys, than to the more derived highly aquatic forms of the Cretaceous and Paleocene. Some morphological features indicate it is more terrestrial than any other genus in the Choristodera.RésuméLazarussuchus inexpectatus, nov. gen., nov. sp., de l’Oligocène est une nouvelle forme de Choristodere qui prolonge l’extension stratigraphique de ce clade jusqu'au Tertiaire moyen. Il présente un remarquable ensemble de caractères primitifs. A cet égard, il ressemble d’avantage à la forme du Jurassique moyen et supérieur, Cteniogenys, qu'aux genres aquatiques plus spécialisés du Crétacé et du Paléocène. Quelques uns des traits morphologiques de Lazarussuchus indiquent que ce genre avait un mode de vie plus terrestre que tout autre Choristodère.
 
Article
Microremains of various sharks, actinopterygians and crocodiles have been recovered from two sites in the Douiret Formation and three sites in the Aïn el Guettar Formation in southern Tunisia. The presence of an actinistian is also suggested based on histological study of hemisegments of lepidotrichia. Convergence in dental enameloid microstructure between neoselachian sharks and actinopterygians sharing a tearing dentition is also documented. The vertebrate assemblage of the Douiret Formation suggests a pre-Aptian age for this formation and the presence of Bernissartia in the Aïn el Guettar Formation confirms faunal exchange between Africa and Europa during the Early Cretaceous.RésuméDes microrestes de plusieurs requins, actinoptérygiens et crocodiles ont été recueillis dans deux sites de la Formation Douiret et trois sites de la Formation Aïn el Guettar dans le Sud tunisien. La présence d’un actinistien est également suggérée d’après des études paléohistologiques d’hémisegments de lépidotriches. Une convergence dans la microstructure de l’émailloïde dentaire des requins néosélaciens et des actinoptérygiens partageant une denture de type arracheur est également illustrée. La faune de vertébrés de la Formation Douiret indique un âge pré-Aptien pour cette formation et la présence de Bernissartia dans la Formation Aïn el Guettar confirme que des échanges faunistiques ont eu lieu entre l’Afrique du Nord et l’Europe durant le Crétacé inférieur.
 
Article
The Early Cretaceous Okurodani Formation of Gifu Prefecture, Central Honshu, Japan, is yielding an assemblage of small freshwater and terrestrial vertebrates which represent some of the oldest specimens of their kind from Japan. Although rare, at least two types of lizards - probably more - have been recovered. The most common form, described here under the name Sakurasaurus shokawensis nov. gen. et sp., is a robust scincomorph with distinctive sculptured frontals and a heterodont dentition in which the anterior teeth are tapering and recurved while the posterior teeth are blunt and striated. Parsimony analysis places it provisionally as a basal scincomorph. Other taxa are represented by isolated elements, including dentaries, maxillae, and some heavily sculptured skull roofing bones which may be anguimorph. This Japanese lizard assemblage differs from roughly contemporaneous assemblages in other parts of the world and thus contributes to our knowledge of Early Cretaceous lizard diversity in general, and to our understanding of the evolution of Asian lizard assemblages.
 
Article
This paper is composed of two parts:1oThe analytical study of species of the genera Stromatocystites (the typical forms issued from Bohemia and Newfoundland are well known), Cambraster and Eikosacystis. The order of Stromatocystitoïdes including three families is proposed for these species.2oSome general remarks concerning the descent of the Stromatocystitoïdes.Effectively, it results from our study that, in America, the Stromatocystitoïdes probably havedfor descendants the Edrioasteroidea fixed upon shells but in Europe, they progressed, by the development of ambulacral appendages, towards the Asteroidea and probably the Carpoïdea initially connected with the endofauna.
 
Article
A definitive systematics of the Neogene European Naticidae has not yet been compiled. There remain some problematic species which have been subject to controversy for a long time. Most of them are composed of forms with similar teleoconchs but different protoconchs. The differences in the protoconchs are significantenough because they involve different types of larval development. Thus, these forms could be considered as distinct species. In this paper we analyze the case of Natica strictiumbilicata Sacco, a species from the Mediterranean Pliocene which has hitherto been confused with Natica pseudoepiglottina Lamarck. The main characters that allow us to state that N. strictiumbilicata is a singular species are the number of whorls of the protoconch, the nucleus diameter and the maximum diameter of the protoconch. We propose the protoconch as a useful tool for systematics of Naticidae. Finally, some paleobiological and paleobiogeographical considerations are discussed.
 
Article
Recent fieldwork in the Miocene basins of northern Thailand yielded the first complete molars of Stegolophodonever found in this country. A complete M3 from Mae Moh (Middle Miocene) and a partial mandible with M2–M3 from Na Sai (Early Miocene), are described with new data on the evolution of the genus in South East Asia. A new species is described in the Early Miocene locality of Na Sai, being the earliest known species of Stegolophodon. The differentiation of tetralophodont forms is much older than was previously thought.RésuméLes travaux récents dans les bassins miocènes du Nord de la Thailande ont mené à la découverte des premièresmolaires complètes de Stegolophodon connues dans ce pays. Une M3 provenant du Miocène moyen de Mae Moh et une mandibule incomplète avec M2–M3, découverte dans le Miocène inférieur de Na Sai, sont notamment décrites avec des données nouvelles sur l'évolution du genre en Asie du Sud-Est. Une nouvelle espèce est décrite dans le gisement du Miocène inférieur de Na Sai; il s'agit de la plus ancienne espèce connue du genre Stegolophodon. La différenciation des formes tétralophodontes est bien plus ancienne que ce que l'on pensait jusqu'à present.
 
Article
The lower levels of the Lipeón Formation, in the Eastern Cordillera, north-west Argentina, yield a marine-dominated palynomorph assemblage, together with graptolites of mid to late mid Llandovery age (Demirastrites convolutus and probably Stimulograptus sedgwickii zones). The palynomorph assemblage is dominated by acritarchs, but also contains algae and terrestrial cryptospores. Crassiangulina variacornuta, considered a potentially good global biostratigraphical marker for the Upper Llandovery is recovered for the first time from the Silurian of Argentina. The occurrence of this species in strata not younger than late Aeronian, and independently dated by graptolites, indicates an early first appearance for Crassiangulina variacornuta, in the Lipeón Formation, below the Aeronian/Telychian boundary. The lower part of the unit corresponds to a quiet marine environment; thus supporting that Crassiangulina variacornuta is a facies-sensitive acritarch.
 
Article
Amussiopecten baranensis (ALMERA & BOFILL, 1896), of the Family Pectinidae, is widespread in Miocene marine sediments from northeastern and southeastern Spain, ranging in age from Early Langhian to Middle Messinian. The shell consists of an outer homogeneous and foliated layer composed of low-magnesium calcite, a middle layer aragonitic, and an inner foliated layer of low-magnesium calcite. Both left and right valves have, in general, the same microstructure and mineralogy except for an outermost thin polygonal layer in the earliest-formed dissoconch of the right valve. The homogeneous structure (dense and granular sublaminae) up to 50 μm thick overlies the sublayer of foliated calcite (regular, irregular and crossed foliated) that extends throughout the whole shell, being thinnest in the dorsal margin and thickening toward the ventral margin. The regular foliated inner layer extends from the beak, where it attains its maximum thickness, to near the adductor muscle scar. The middle layer is the most complex in structure and distribution, being composed of three sublayers which from exterior to interior are : 1) aragonitic simple crossed lamellar, 2) aragonitic prismatic (myostracal), and 3) aragonitic complex crossed lamellar. The latter sublayer in the internal shell surface extends to the area interior to the pallial line. Prominent features of the middle layer are the asymmetrical distribution of the prismatic structure (absent in the anterior margin), and the thinning of the three sublayers both in radial and antero-posterior directions. The divaricate microsculpture extending on the umbonal area and auricles in both valves originates from the granular calcite of the homogeneous structure. δ180 values of the outer foliated layer from the ventral margin suggest that A. baranensis segregates its calcite in isotopic equilibrium with ambient sea-water, and thus affords a valuable tool in paleoenvironmental studies.
 
Article
The morphological analysis of the structural plan of the Radiocyathids skeleton implies a closer relationship to Receptaculitids than to Archaeocyathids. As a working hypothesis, they may possibly form a link between part or all of these two groups and use as a test for the validity of the new kingdom Archaeata proposed by I. T. Zhuravleva & E. I. Miagkova.RésuméL'analyse morphologique structurale du squelettedes Radiocyathes montre une relation plus étroite avec les Receptaculites qu'avec les Archéocyathes. A titre d'hypothèse de travail, ils pourraient être considérés comme un lien entre ces deux groupes et servir de test de validité pour le nouvel embranchement des Archaeata proposé par I. T. Zhuravleva & E. I. Miagkova.
 
Article
A diverse vertebrate fauna including representatives of at least 22 families of land mammals is known from 500+m thick Estratos Salla of Deseadan (early Oligocene) age in the Salla-Luribay Basin, about 90 km SW of La Paz, Bolivia. Eight principal fossil levels are identified west of Salla concentrated within a 160 m section. A preliminary report on the geology of the Estratos Salla is given, with maps and stratigraphic sections of the fossiliferous levels and localities. Four specimens of fossil marsupials from the Salla-Luribay Basin in the GEOBOL collection in La Paz are described. Part of a mandibular ramus with two molars represents a new borhyaenid (Sallacyon hoffstetteri gen. et sp. nov.); a relatively complete mandible with teeth is refered to the borhyaenid Notogale mitis (Ameghino, 1897); an associated upper and lower dentition is referred to the palaeothentine (Caenolestidae) Palaeothentes boliviensis Patterson & Marshall, 1978; and a maxillary fragment with poorly preserved M1–4 apparently represents an enormous palaeothentine.
 
Article
The solute Maennilia estonica nov. gen. et nov. sp. (Maenniliidae, nov. fam.) from the middle Caradoc Keila Horizon of the village of Vasalemma, near the town of Keila, near Tallin, Estonia is reconstructed and described. Remarkable features include: the hydropore developed as a madreporite and penetrated by the gonopore; ringshaped major plates in the fore tail, visibly formed by the fusion of smaller plates; a symmetrical mid tail, with dorsal and ventral series of ossicles extending forwards to meet the fore-tail rings in the mid line; an anterior lobe projecting leftwards and better developed in large than small individuals; and large size. Maennilia estonica may have lived with the ventral face up. The presence of a branchial pore could not be established. Ontogenetic changes in the anterior lobe suggest that the gonad was anteriorly located in the head, as in other solutes. Maenniliidae nov. fam. comprising M. estonica and Heckericystis kuckersiana (Hecker) 1940, and with Maennilia estonica as the type species, is proposed with three autapomorphies: the gonopore penetrates the hydropore, the mid tail has a peculiar symmetrical structure and the head skeleton is relatively rigid. The Maeniliidae have rings in the fore tail visibly formed by the fusion of smaller plates. Among other solutes, only Dendrocystites sedgwickiBarrande, 1887 seems to share this feature which should therefore probably be seen as a synapomorphy of the Maenniliidae with that species. Within the chordate stem group, the Maenniliidae with Dendrocystites sedgwicki probably represent a plesion crownward of the Iowacystidae and anti-crownward of Dendrocystoides scoticus (Bather) 1913. Hecker's reconstruction of H. kuckersiana is partly mistaken. Isolated hind-tail ossicles of ”Dendrocystites” rossicusJaekel, 1901, from the Llanvirn near Pavlovsk in the St. Petersburg area of Russia, suggest a solute of very great size i.e. with a guessed total length of perhaps 300 mm, making it by far the largest known solute.RésuméLe Soluta Maennilia estonica nov. gen. et nov. sp., du Caradocien moyen de l'horizon de Keila du village de Vasalemma, près de la ville de Keila dans la région de Tallin, Estonie, est reconstitué et décrit. Les traits remarquables en sont les suivants: un hydropore développé en madréporite et traversé par le gonopore; des plaques majeures de la partie antérieure de la queue en forme d'anneau et visiblement formées par la fusion de plaques plus petites; une partie moyenne de la queue symétrique avec des séries de grandes plaques dorsales et ventrales qui se prolongent dans la ligne médiane jusqu'à l'extrémité postérieure des plaques majeures de la partie antérieure de la queue; un lobe antérieur de la tête qui s'étend vers la gauche et qui est plus developpé chez les individus de grande taille que chez les petits; la taille importante de l'espèce. Il est possible que Maennilia estonica vivait avec la face ventrale vers le côté supérieur. Aucun pore branchial n'a pu être identifié. Des changements ontogénétiques de la forme du lobe antérieur indiquent que la gonade était située antérieurement dans la tête, comme chez les autres Soluta. La nouvelle famille des Maenniliidae, constituée par Maennilia estonica et Heckericystis kuckersiana (Hecker) 1940, avec Maennillia estonica comme espèce type, est proposée avec trois autapomorphies: un gonopore qui traverse le madréporite, la condition relativement rigide du squelette de la tête et une structure symétrique et particulière de la partie moyenne de la queue. Les Maenniliidés ont des anneaux majeurs dans la partie antérieure de la queue qui sont visiblement formés par la fusion de plaques plus petites. Parmi les autres Soluta ce caractèrene ne semble être partagé qu'avec l'espèce Dendrocystites sedgwickiBarrande, 1887 et représente, selon toute probabilité, une synapomorphie avec elle. Les Maenniliidés et Dendrocystites sedgwicki représentent, dans le groupe souche des chordés, un plésion plus proche du groupe cime que les Iowacystidés et moins proche que le plésion de Dendrocystoides scoticus (Bather) 1913. La reconstitution par Hecker de Heckericystis kuckersiana contient des erreurs. Des plaques isolées massives de la queue postérieure de “Dendrocystites” rossicusJaekel, 1901, du Llanvirnien des environs de la ville de Pavlovsk dans la région de St.-Pétersbourg, indiquent un Soluta de très grande taille (une longueur totale estimée d'environ 300 mm) qui en fait donc le plus grand des Soluta connus.
 
Article
The study of the primitive gerbil remains of Pseudomeriones, recovered from the micromammalian sites of Paliambela-B and Monasteri (Latest Miocene, Northern Greece), gives evidence for a new species, which is characterized by its large size and simple molar morphology. A cladistic analysis based on dental characters affiliates this form with P. rhodius and P. pythagorasi and enables an intrageneric phylogenetic scenario.
 
Top-cited authors
Daniel Vachard
  • Université de Lille
Denis Geraads
  • Muséum National d'Histoire Naturelle
Pierre René Mein
  • Claude Bernard University Lyon 1
Eric Buffetaut
  • French National Centre for Scientific Research
Cappetta Henri
  • Université de Montpellier